Dropping Transmission of Uplink Signals of a Radio Access Technology

ABSTRACT

A wireless device receives: a first maximum total transmit power allowed for a first cell group of a first type of radio access technology; and a second maximum total transmit power allowed for a second cell group of a second type of radio access technology. It is determined that a total transmission power exceeds a value based on: a first power for transmission of first uplink signal(s) via the first cell group, and a second power for transmission of second uplink signal(s) via the second cell group. The first and second powers are less than or equal to the first and second maximum total transmit powers respectively. Scheduled transmission of the first uplink signal(s) of the first cell group is dropped in response to the first cell group being of the first type of radio access technology. Second uplink signal(s) are transmitted to a base station.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/590,982, filed May 9, 2017, which claims the benefit of U.S.Provisional Application No. 62/333,789, filed May 9, 2016, which ishereby incorporated by reference in its entirety.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Examples of several of the various embodiments of the present disclosureare described herein with reference to the drawings.

FIG. 1 is a diagram depicting example sets of OFDM subcarriers as per anaspect of an embodiment of the present disclosure.

FIG. 2 is a diagram depicting an example transmission time and receptiontime for two carriers in a carrier group as per an aspect of anembodiment of the present disclosure.

FIG. 3 is an example diagram depicting OFDM radio resources as per anaspect of an embodiment of the present disclosure.

FIG. 4 is an example block diagram of a base station and a wirelessdevice as per an aspect of an embodiment of the present disclosure.

FIG. 5A, FIG. 5B, FIG. 5C and FIG. 5D are example diagrams for uplinkand downlink signal transmission as per an aspect of an embodiment ofthe present disclosure.

FIG. 6 is an example diagram for a protocol structure with CA and DC asper an aspect of an embodiment of the present disclosure.

FIG. 7 is an example diagram for a protocol structure with CA and DC asper an aspect of an embodiment of the present disclosure.

FIG. 8 shows example TAG configurations as per an aspect of anembodiment of the present disclosure.

FIG. 9 is an example message flow in a random access process in asecondary TAG as per an aspect of an embodiment of the presentdisclosure.

FIG. 10 is an example diagram depicting a downlink burst as per anaspect of an embodiment of the present disclosure.

FIG. 11 is an example diagram depicting uplink transmissions via aplurality of cells as per an aspect of an embodiment of the presentdisclosure.

FIG. 12 is an example diagram depicting uplink transmissions via aplurality of cells as per an aspect of an embodiment of the presentdisclosure.

FIG. 13 is an example diagram depicting uplink transmissions via aplurality of cells as per an aspect of an embodiment of the presentdisclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Example embodiments of the present disclosure enable operation ofcarrier aggregation. Embodiments of the technology disclosed herein maybe employed in the technical field of multicarrier communicationsystems.

The following Acronyms are used throughout the present disclosure:

ASIC application-specific integrated circuit

BPSK binary phase shift keying

CA carrier aggregation

CSI channel state information

CDMA code division multiple access

CSS common search space

CPLD complex programmable logic devices

CC component carrier

DL downlink

DCI downlink control information

DC dual connectivity

EPC evolved packet core

E-UTRAN evolved-universal terrestrial radio access network

FPGA field programmable gate arrays

FDD frequency division multiplexing

HDL hardware description languages

HARQ hybrid automatic repeat request

IE information element

LAA licensed assisted access

LTE long term evolution

MCG master cell group

MeNB master evolved node B

MIB master information block

MAC media access control

MAC media access control

MME mobility management entity

NAS non-access stratum

OFDM orthogonal frequency division multiplexing

PDCP packet data convergence protocol

PDU packet data unit

PHY physical

PDCCH physical downlink control channel

PHICH physical HARQ indicator channel

PUCCH physical uplink control channel

PUSCH physical uplink shared channel

PCell primary cell

PCell primary cell

PCC primary component carrier

PSCell primary secondary cell

pTAG primary timing advance group

QAM quadrature amplitude modulation

QPSK quadrature phase shift keying

RBG Resource Block Groups

RLC radio link control

RRC radio resource control

RA random access

RB resource blocks

SCC secondary component carrier

SCell secondary cell

Scell secondary cells

SCG secondary cell group

SeNB secondary evolved node B

sTAGs secondary timing advance group

SDU service data unit

S-GW serving gateway

SRB signaling radio bearer

SC-OFDM single carrier-OFDM

SFN system frame number

SIB system information block

TAI tracking area identifier

TAT time alignment timer

TDD time division duplexing

TDMA time division multiple access

TA timing advance

TAG timing advance group

TB transport block

UL uplink

UE user equipment

VHDL VHSIC hardware description language

Example embodiments of the disclosure may be implemented using variousphysical layer modulation and transmission mechanisms. Exampletransmission mechanisms may include, but are not limited to: CDMA, OFDM,TDMA, Wavelet technologies, and/or the like. Hybrid transmissionmechanisms such as TDMA/CDMA, and OFDM/CDMA may also be employed.Various modulation schemes may be applied for signal transmission in thephysical layer. Examples of modulation schemes include, but are notlimited to: phase, amplitude, code, a combination of these, and/or thelike. An example radio transmission method may implement QAM using BPSK,QPSK, 16-QAM, 64-QAM, 256-QAM, and/or the like. Physical radiotransmission may be enhanced by dynamically or semi-dynamically changingthe modulation and coding scheme depending on transmission requirementsand radio conditions.

FIG. 1 is a diagram depicting example sets of OFDM subcarriers as per anaspect of an embodiment of the present disclosure. As illustrated inthis example, arrow(s) in the diagram may depict a subcarrier in amulticarrier OFDM system. The OFDM system may use technology such asOFDM technology, DFTS-OFDM, SC-OFDM technology, or the like. Forexample, arrow 101 shows a subcarrier transmitting information symbols.FIG. 1 is for illustration purposes, and a typical multicarrier OFDMsystem may include more subcarriers in a carrier. For example, thenumber of subcarriers in a carrier may be in the range of 10 to 10,000subcarriers. FIG. 1 shows two guard bands 106 and 107 in a transmissionband. As illustrated in FIG. 1, guard band 106 is between subcarriers103 and subcarriers 104. The example set of subcarriers A 102 includessubcarriers 103 and subcarriers 104. FIG. 1 also illustrates an exampleset of subcarriers B 105. As illustrated, there is no guard band betweenany two subcarriers in the example set of subcarriers B 105. Carriers ina multicarrier OFDM communication system may be contiguous carriers,non-contiguous carriers, or a combination of both contiguous andnon-contiguous carriers.

FIG. 2 is a diagram depicting an example transmission time and receptiontime for two carriers as per an aspect of an embodiment of the presentdisclosure. A multicarrier OFDM communication system may include one ormore carriers, for example, ranging from 1 to 10 carriers. Carrier A 204and carrier B 205 may have the same or different timing structures.Although FIG. 2 shows two synchronized carriers, carrier A 204 andcarrier B 205 may or may not be synchronized with each other. Differentradio frame structures may be supported for FDD and TDD duplexmechanisms. FIG. 2 shows an example FDD frame timing. Downlink anduplink transmissions may be organized into radio frames 201. In thisexample, the radio frame duration is 10 msec. Other frame durations, forexample, in the range of 1 to 100 msec may also be supported. In thisexample, each 10 ms radio frame 201 may be divided into ten equallysized subframes 202. Other subframe durations such as 0.5 msec, 1 msec,2 msec, and 5 msec may also be supported. Subframe(s) may consist of twoor more slots (for example, slots 206 and 207). For the example of FDD,10 subframes may be available for downlink transmission and 10 subframesmay be available for uplink transmissions in each 10 ms interval. Uplinkand downlink transmissions may be separated in the frequency domain.Slot(s) may include a plurality of OFDM symbols 203. The number of OFDMsymbols 203 in a slot 206 may depend on the cyclic prefix length andsubcarrier spacing.

FIG. 3 is a diagram depicting OFDM radio resources as per an aspect ofan embodiment of the present disclosure. The resource grid structure intime 304 and frequency 305 is illustrated in FIG. 3. The quantity ofdownlink subcarriers or RBs (in this example 6 to100 RBs) may depend, atleast in part, on the downlink transmission bandwidth 306 configured inthe cell. The smallest radio resource unit may be called a resourceelement (e.g. 301). Resource elements may be grouped into resourceblocks (e.g. 302). Resource blocks may be grouped into larger radioresources called Resource Block Groups (RBG) (e.g. 303). The transmittedsignal in slot 206 may be described by one or several resource grids ofa plurality of subcarriers and a plurality of OFDM symbols. Resourceblocks may be used to describe the mapping of certain physical channelsto resource elements. Other pre-defined groupings of physical resourceelements may be implemented in the system depending on the radiotechnology. For example, 24 subcarriers may be grouped as a radio blockfor a duration of 5 msec. In an illustrative example, a resource blockmay correspond to one slot in the time domain and 180 kHz in thefrequency domain (for 15 KHz subcarrier bandwidth and 12 subcarriers).

FIG. 5A, FIG. 5B, FIG. 5C and FIG. 5D are example diagrams for uplinkand downlink signal transmission as per an aspect of an embodiment ofthe present disclosure. FIG. 5A shows an example uplink physicalchannel. The baseband signal representing the physical uplink sharedchannel may perform the following processes. These functions areillustrated as examples and it is anticipated that other mechanisms maybe implemented in various embodiments. The functions may comprisescrambling, modulation of scrambled bits to generate complex-valuedsymbols, mapping of the complex-valued modulation symbols onto one orseveral transmission layers, transform precoding to generatecomplex-valued symbols, precoding of the complex-valued symbols, mappingof precoded complex-valued symbols to resource elements, generation ofcomplex-valued time-domain DFTS-OFDM/SC-FDMA signal for each antennaport, and/or the like.

Example modulation and up-conversion to the carrier frequency of thecomplex-valued DFTS-OFDM/SC-FDMA baseband signal for each antenna portand/or the complex-valued PRACH baseband signal is shown in FIG. 5B.Filtering may be employed prior to transmission.

An example structure for Downlink Transmissions is shown in FIG. 5C. Thebaseband signal representing a downlink physical channel may perform thefollowing processes. These functions are illustrated as examples and itis anticipated that other mechanisms may be implemented in variousembodiments. The functions include scrambling of coded bits in each ofthe codewords to be transmitted on a physical channel; modulation ofscrambled bits to generate complex-valued modulation symbols; mapping ofthe complex-valued modulation symbols onto one or several transmissionlayers; precoding of the complex-valued modulation symbols on each layerfor transmission on the antenna ports; mapping of complex-valuedmodulation symbols for each antenna port to resource elements;generation of complex-valued time-domain OFDM signal for each antennaport, and/or the like.

Example modulation and up-conversion to the carrier frequency of thecomplex-valued OFDM baseband signal for each antenna port is shown inFIG. 5D. Filtering may be employed prior to transmission.

FIG. 4 is an example block diagram of a base station 401 and a wirelessdevice 406, as per an aspect of an embodiment of the present disclosure.A communication network 400 may include at least one base station 401and at least one wireless device 406. The base station 401 may includeat least one communication interface 402, at least one processor 403,and at least one set of program code instructions 405 stored innon-transitory memory 404 and executable by the at least one processor403. The wireless device 406 may include at least one communicationinterface 407, at least one processor 408, and at least one set ofprogram code instructions 410 stored in non-transitory memory 409 andexecutable by the at least one processor 408. Communication interface402 in base station 401 may be configured to engage in communicationwith communication interface 407 in wireless device 406 via acommunication path that includes at least one wireless link 411.Wireless link 411 may be a bi-directional link. Communication interface407 in wireless device 406 may also be configured to engage in acommunication with communication interface 402 in base station 401. Basestation 401 and wireless device 406 may be configured to send andreceive data over wireless link 411 using multiple frequency carriers.According to aspects of an embodiments, transceiver(s) may be employed.A transceiver is a device that includes both a transmitter and receiver.Transceivers may be employed in devices such as wireless devices, basestations, relay nodes, and/or the like. Example embodiments for radiotechnology implemented in communication interface 402, 407 and wirelesslink 411 are illustrated are FIG. 1, FIG. 2, FIG. 3, FIG. 5, andassociated text.

An interface may be a hardware interface, a firmware interface, asoftware interface, and/or a combination thereof. The hardware interfacemay include connectors, wires, electronic devices such as drivers,amplifiers, and/or the like. A software interface may include codestored in a memory device to implement protocol(s), protocol layers,communication drivers, device drivers, combinations thereof, and/or thelike. A firmware interface may include a combination of embeddedhardware and code stored in and/or in communication with a memory deviceto implement connections, electronic device operations, protocol(s),protocol layers, communication drivers, device drivers, hardwareoperations, combinations thereof, and/or the like.

The term configured may relate to the capacity of a device whether thedevice is in an operational or non-operational state. Configured mayalso refer to specific settings in a device that effect the operationalcharacteristics of the device whether the device is in an operational ornon-operational state. In other words, the hardware, software, firmware,registers, memory values, and/or the like may be “configured” within adevice, whether the device is in an operational or nonoperational state,to provide the device with specific characteristics. Terms such as “acontrol message to cause in a device” may mean that a control messagehas parameters that may be used to configure specific characteristics inthe device, whether the device is in an operational or non-operationalstate.

According to various aspects of an embodiment, an LTE network mayinclude a multitude of base stations, providing a user planePDCP/RLC/MAC/PHY and control plane (RRC) protocol terminations towardsthe wireless device. The base station(s) may be interconnected withother base station(s) (for example, interconnected employing an X2interface). Base stations may also be connected employing, for example,an S1 interface to an EPC. For example, base stations may beinterconnected to the MME employing the S1-MME interface and to the S-G)employing the S1-U interface. The S1 interface may support amany-to-many relation between MMEs/Serving Gateways and base stations. Abase station may include many sectors for example: 1, 2, 3, 4, or 6sectors. A base station may include many cells, for example, rangingfrom 1 to 50 cells or more. A cell may be categorized, for example, as aprimary cell or secondary cell. At RRC connectionestablishment/re-establishment/handover, one serving cell may providethe NAS (non-access stratum) mobility information (e.g. TAI), and at RRCconnection re-establishment/handover, one serving cell may provide thesecurity input. This cell may be referred to as the Primary Cell(PCell). In the downlink, the carrier corresponding to the PCell may bethe Downlink Primary Component Carrier (DL PCC), while in the uplink,the carrier corresponding to the PCell may be the Uplink PrimaryComponent Carrier (UL PCC). Depending on wireless device capabilities,Secondary Cells (SCells) may be configured to form together with thePCell a set of serving cells. In the downlink, the carrier correspondingto an SCell may be a Downlink Secondary Component Carrier (DL SCC),while in the uplink, it may be an Uplink Secondary Component Carrier (ULSCC). An SCell may or may not have an uplink carrier.

A cell, comprising a downlink carrier and optionally an uplink carrier,may be assigned a physical cell ID and a cell index. A carrier (downlinkor uplink) may belong to only one cell. The cell ID or Cell index mayalso identify the downlink carrier or uplink carrier of the cell(depending on the context it is used). In the specification, cell ID maybe equally referred to a carrier ID, and cell index may be referred tocarrier index. In implementation, the physical cell ID or cell index maybe assigned to a cell. A cell ID may be determined using asynchronization signal transmitted on a downlink carrier. A cell indexmay be determined using RRC messages. For example, when thespecification refers to a first physical cell ID for a first downlinkcarrier, the specification may mean the first physical cell ID is for acell comprising the first downlink carrier. The same concept may apply,for example, to carrier activation. When the specification indicatesthat a first carrier is activated, the specification may also mean thatthe cell comprising the first carrier is activated.

Embodiments may be configured to operate as needed. The disclosedmechanism may be performed when certain criteria are met, for example,in a wireless device, a base station, a radio environment, a network, acombination of the above, and/or the like. Example criteria may bebased, at least in part, on for example, traffic load, initial systemset up, packet sizes, traffic characteristics, a combination of theabove, and/or the like. When the one or more criteria are met, variousexample embodiments may be applied. Therefore, it may be possible toimplement example embodiments that selectively implement disclosedprotocols.

A base station may communicate with a mix of wireless devices. Wirelessdevices may support multiple technologies, and/or multiple releases ofthe same technology. Wireless devices may have some specificcapability(ies) depending on its wireless device category and/orcapability(ies). A base station may comprise multiple sectors. When thisdisclosure refers to a base station communicating with a plurality ofwireless devices, this disclosure may refer to a subset of the totalwireless devices in a coverage area. This disclosure may refer to, forexample, a plurality of wireless devices of a given LTE release with agiven capability and in a given sector of the base station. Theplurality of wireless devices in this disclosure may refer to a selectedplurality of wireless devices, and/or a subset of total wireless devicesin a coverage area which perform according to disclosed methods, and/orthe like. There may be a plurality of wireless devices in a coveragearea that may not comply with the disclosed methods, for example,because those wireless devices perform based on older releases of LTEtechnology.

FIG. 6 and FIG. 7 are example diagrams for protocol structure with CAand DC as per an aspect of an embodiment of the present disclosure.E-UTRAN may support Dual Connectivity (DC) operation whereby a multipleRX/TX UE in RRC_CONNECTED may be configured to utilize radio resourcesprovided by two schedulers located in two eNBs connected via a non-idealbackhaul over the X2 interface. eNBs involved in DC for a certain UE mayassume two different roles: an eNB may either act as an MeNB or as anSeNB. In DC a UE may be connected to one MeNB and one SeNB. Mechanismsimplemented in DC may be extended to cover more than two eNBs. FIG. 7illustrates one example structure for the UE side MAC entities when aMaster Cell Group (MCG) and a Secondary Cell Group (SCG) are configured,and it may not restrict implementation. Media Broadcast MulticastService (MBMS) reception is not shown in this figure for simplicity.

In DC, the radio protocol architecture that a particular bearer uses maydepend on how the bearer is setup. Three alternatives may exist, an MCGbearer, an SCG bearer and a split bearer as shown in FIG. 6. RRC may belocated in MeNB and SRBs may be configured as a MCG bearer type and mayuse the radio resources of the MeNB. DC may also be described as havingat least one bearer configured to use radio resources provided by theSeNB. DC may or may not be configured/implemented in example embodimentsof the disclosure.

In the case of DC, the UE may be configured with two MAC entities: oneMAC entity for MeNB, and one MAC entity for SeNB. In DC, the configuredset of serving cells for a UE may comprise two subsets: the Master CellGroup (MCG) containing the serving cells of the MeNB, and the SecondaryCell Group (SCG) containing the serving cells of the SeNB. For a SCG,one or more of the following may be applied. At least one cell in theSCG may have a configured UL CC and one of them, named PSCell (or PCellof SCG, or sometimes called PCell), may be configured with PUCCHresources. When the SCG is configured, there may be at least one SCGbearer or one Split bearer. Upon detection of a physical layer problemor a random access problem on a PSCell, or the maximum number of RLCretransmissions has been reached associated with the SCG, or upondetection of an access problem on a PSCell during a SCG addition or aSCG change: a RRC connection re-establishment procedure may not betriggered, UL transmissions towards cells of the SCG may be stopped, anda MeNB may be informed by the UE of a SCG failure type. For splitbearer, the DL data transfer over the MeNB may be maintained. The RLC AMbearer may be configured for the split bearer. Like a PCell, a PSCellmay not be de-activated. A PSCell may be changed with a SCG change (forexample, with a security key change and a RACH procedure), and/orneither a direct bearer type change between a Split bearer and a SCGbearer nor simultaneous configuration of a SCG and a Split bearer may besupported.

With respect to the interaction between a MeNB and a SeNB, one or moreof the following principles may be applied. The MeNB may maintain theRRM measurement configuration of the UE and may, (for example, based onreceived measurement reports or traffic conditions or bearer types),decide to ask a SeNB to provide additional resources (serving cells) fora UE. Upon receiving a request from the MeNB, a SeNB may create acontainer that may result in the configuration of additional servingcells for the UE (or decide that it has no resource available to do so).For UE capability coordination, the MeNB may provide (part of) the ASconfiguration and the UE capabilities to the SeNB. The MeNB and the SeNBmay exchange information about a UE configuration by employing RRCcontainers (inter-node messages) carried in X2 messages. The SeNB mayinitiate a reconfiguration of its existing serving cells (for example, aPUCCH towards the SeNB). The SeNB may decide which cell is the PSCellwithin the SCG. The MeNB may not change the content of the RRCconfiguration provided by the SeNB. In the case of a SCG addition and aSCG SCell addition, the MeNB may provide the latest measurement resultsfor the SCG cell(s). Both a MeNB and a SeNB may know the SFN andsubframe offset of each other by OAM, (for example, for the purpose ofDRX alignment and identification of a measurement gap). In an example,when adding a new SCG SCell, dedicated RRC signaling may be used forsending required system information of the cell as for CA, except forthe SFN acquired from a MIB of the PSCell of a SCG.

In an example, serving cells may be grouped in a TA group (TAG). Servingcells in one TAG may use the same timing reference. For a given TAG,user equipment (UE) may use at least one downlink carrier as a timingreference. For a given TAG, a UE may synchronize uplink subframe andframe transmission timing of uplink carriers belonging to the same TAG.In an example, serving cells having an uplink to which the same TAapplies may correspond to serving cells hosted by the same receiver. AUE supporting multiple TAs may support two or more TA groups. One TAgroup may contain the PCell and may be called a primary TAG (pTAG). In amultiple TAG configuration, at least one TA group may not contain thePCell and may be called a secondary TAG (sTAG). In an example, carrierswithin the same TA group may use the same TA value and/or the sametiming reference. When DC is configured, cells belonging to a cell group(MCG or SCG) may be grouped into multiple TAGs including a pTAG and oneor more sTAGs.

FIG. 8 shows example TAG configurations as per an aspect of anembodiment of the present disclosure. In Example 1, pTAG comprises aPCell, and an sTAG comprises SCell1. In Example 2, a pTAG comprises aPCell and SCell1, and an sTAG comprises SCell2 and SCell3. In Example 3,pTAG comprises PCell and SCell1, and an sTAG1 includes SCell2 andSCell3, and sTAG2 comprises SCell4. Up to four TAGs may be supported ina cell group (MCG or SCG) and other example TAG configurations may alsobe provided. In various examples in this disclosure, example mechanismsare described for a pTAG and an sTAG. Some of the example mechanisms maybe applied to configurations with multiple sTAGs.

In an example, an eNB may initiate an RA procedure via a PDCCH order foran activated SCell. This PDCCH order may be sent on a scheduling cell ofthis SCell. When cross carrier scheduling is configured for a cell, thescheduling cell may be different than the cell that is employed forpreamble transmission, and the PDCCH order may include an SCell index.At least a non-contention based RA procedure may be supported forSCell(s) assigned to sTAG(s).

FIG. 9 is an example message flow in a random access process in asecondary TAG as per an aspect of an embodiment of the presentdisclosure. An eNB transmits an activation command 600 to activate anSCell. A preamble 602 (Msg1) may be sent by a UE in response to a PDCCHorder 601 on an SCell belonging to an sTAG. In an example embodiment,preamble transmission for SCells may be controlled by the network usingPDCCH format 1A. Msg2 message 603 (RAR: random access response) inresponse to the preamble transmission on the SCell may be addressed toRA-RNTI in a PCell common search space (CSS). Uplink packets 604 may betransmitted on the SCell in which the preamble was transmitted.

According to an embodiment, initial timing alignment may be achievedthrough a random access procedure. This may involve a UE transmitting arandom access preamble and an eNB responding with an initial TA commandNTA (amount of timing advance) within a random access response window.The start of the random access preamble may be aligned with the start ofa corresponding uplink subframe at the UE assuming NTA=0. The eNB mayestimate the uplink timing from the random access preamble transmittedby the UE. The TA command may be derived by the eNB based on theestimation of the difference between the desired UL timing and theactual UL timing. The UE may determine the initial uplink transmissiontiming relative to the corresponding downlink of the sTAG on which thepreamble is transmitted.

The mapping of a serving cell to a TAG may be configured by a servingeNB with RRC signaling. The mechanism for TAG configuration andreconfiguration may be based on RRC signaling. According to variousaspects of an embodiment, when an eNB performs an SCell additionconfiguration, the related TAG configuration may be configured for theSCell. In an example embodiment, an eNB may modify the TAG configurationof an SCell by removing (releasing) the SCell and adding(configuring) anew SCell (with the same physical cell ID and frequency) with an updatedTAG ID. The new SCell with the updated TAG ID may initially be inactivesubsequent to being assigned the updated TAG ID. The eNB may activatethe updated new SCell and start scheduling packets on the activatedSCell. In an example implementation, it may not be possible to changethe TAG associated with an SCell, but rather, the SCell may need to beremoved and a new SCell may need to be added with another TAG. Forexample, if there is a need to move an SCell from an sTAG to a pTAG, atleast one RRC message, (for example, at least one RRC reconfigurationmessage), may be send to the UE to reconfigure TAG configurations byreleasing the SCell and then configuring the SCell as a part of thepTAG. When an SCell is added/configured without a TAG index, the SCellmay be explicitly assigned to the pTAG. The PCell may not change its TAgroup and may be a member of the pTAG.

The purpose of an RRC connection reconfiguration procedure may be tomodify an RRC connection, (for example, to establish, modify and/orrelease RBs, to perform handover, to setup, modify, and/or releasemeasurements, to add, modify, and/or release SCells). If the receivedRRC Connection Reconfiguration message includes the sCellToReleaseList,the UE may perform an SCell release. If the received RRC ConnectionReconfiguration message includes the sCellToAddModList, the UE mayperform SCell additions or modification.

In LTE Release-10 and Release-11 CA, a PUCCH may only be transmitted onthe PCell (PSCell) to an eNB. In LTE-Release 12 and earlier, a UE maytransmit PUCCH information on one cell (PCell or PSCell) to a given eNB.

As the number of CA capable UEs and also the number of aggregatedcarriers increase, the number of PUCCHs and also the PUCCH payload sizemay increase. Accommodating the PUCCH transmissions on the PCell maylead to a high PUCCH load on the PCell. A PUCCH on an SCell may beintroduced to offload the PUCCH resource from the PCell. More than onePUCCH may be configured for example, a PUCCH on a PCell and anotherPUCCH on an SCell. In the example embodiments, one, two or more cellsmay be configured with PUCCH resources for transmitting CSI/ACK/NACK toa base station. Cells may be grouped into multiple PUCCH groups, and oneor more cell within a group may be configured with a PUCCH. In anexample configuration, one SCell may belong to one PUCCH group. SCellswith a configured PUCCH transmitted to a base station may be called aPUCCH SCell, and a cell group with a common PUCCH resource transmittedto the same base station may be called a PUCCH group.

In an example embodiment, a MAC entity may have a configurable timertimeAlignmentTimer per TAG. The timeAlignmentTimer may be used tocontrol how long the MAC entity considers the Serving Cells belonging tothe associated TAG to be uplink time aligned. The MAC entity may, when aTiming Advance Command MAC control element is received, apply the TimingAdvance Command for the indicated TAG; start or restart thetimeAlignmentTimer associated with the indicated TAG. The MAC entitymay, when a Timing Advance Command is received in a Random AccessResponse message for a serving cell belonging to a TAG and/orif theRandom Access Preamble was not selected by the MAC entity, apply theTiming Advance Command for this TAG and start or restart thetimeAlignmentTimer associated with this TAG. Otherwise, if thetimeAlignmentTimer associated with this TAG is not running, the TimingAdvance Command for this TAG may be applied and the timeAlignmentTimerassociated with this TAG started. When the contention resolution isconsidered not successful, a timeAlignmentTimer associated with this TAGmay be stopped. Otherwise, the MAC entity may ignore the received TimingAdvance Command.

In example embodiments, a timer is running once it is started, until itis stopped or until it expires; otherwise it may not be running. A timercan be started if it is not running or restarted if it is running. Forexample, a timer may be started or restarted from its initial value.

Example embodiments of the disclosure may enable operation ofmulti-carrier communications. Other example embodiments may comprise anon-transitory tangible computer readable media comprising instructionsexecutable by one or more processors to cause operation of multi-carriercommunications. Yet other example embodiments may comprise an article ofmanufacture that comprises a non-transitory tangible computer readablemachine-accessible medium having instructions encoded thereon forenabling programmable hardware to cause a device (e.g. wirelesscommunicator, UE, base station, etc.) to enable operation ofmulti-carrier communications. The device may include processors, memory,interfaces, and/or the like. Other example embodiments may comprisecommunication networks comprising devices such as base stations,wireless devices (or user equipment: UE), servers, switches, antennas,and/or the like.

The amount of data traffic carried over cellular networks is expected toincrease for many years to come. The number of users/devices isincreasing and each user/device accesses an increasing number andvariety of services, e.g. video delivery, large files, images. This mayrequire not only high capacity in the network, but also provisioningvery high data rates to meet customers' expectations on interactivityand responsiveness. More spectrum may therefore needed for cellularoperators to meet the increasing demand. Considering user expectationsof high data rates along with seamless mobility, it may be beneficialthat more spectrum be made available for deploying macro cells as wellas small cells for cellular systems.

Striving to meet the market demands, there has been increasing interestfrom operators in deploying some complementary access utilizingunlicensed spectrum to meet the traffic growth. This is exemplified bythe large number of operator-deployed Wi-Fi networks and the 3GPPstandardization of LTE/WLAN interworking solutions. This interestindicates that unlicensed spectrum, when present, may be an effectivecomplement to licensed spectrum for cellular operators to helpaddressing the traffic explosion in some scenarios, such as hotspotareas. LAA may offer an alternative for operators to make use ofunlicensed spectrum while managing one radio network, thus offering newpossibilities for optimizing the network's efficiency.

In an example embodiment, Listen-before-talk (clear channel assessment)may be implemented for transmission in an LAA cell. In alisten-before-talk (LBT) procedure, equipment may apply a clear channelassessment (CCA) check before using the channel. For example, the CCAmay utilize at least energy detection to determine the presence orabsence of other signals on a channel in order to determine if a channelis occupied or clear, respectively. For example, European and Japaneseregulations mandate the usage of LBT in the unlicensed bands. Apart fromregulatory requirements, carrier sensing via LBT may be one way for fairsharing of the unlicensed spectrum.

In an example embodiment, discontinuous transmission on an unlicensedcarrier with limited maximum transmission duration may be enabled. Someof these functions may be supported by one or more signals to betransmitted from the beginning of a discontinuous LAA downlinktransmission. Channel reservation may be enabled by the transmission ofsignals, by an LAA node, after gaining channel access via a successfulLBT operation, so that other nodes that receive the transmitted signalwith energy above a certain threshold sense the channel to be occupied.Functions that may need to be supported by one or more signals for LAAoperation with discontinuous downlink transmission may include one ormore of the following: detection of the LAA downlink transmission(including cell identification) by UEs, time & frequency synchronizationof UEs, and/or the like.

In an example embodiment, a DL LAA design may employ subframe boundaryalignment according to LTE-A carrier aggregation timing relationshipsacross serving cells aggregated by CA. This may not imply that the eNBtransmissions can start only at the subframe boundary. LAA may supporttransmitting PDSCH when not all OFDM symbols are available fortransmission in a subframe according to LBT. Delivery of necessarycontrol information for the PDSCH may also be supported.

An LBT procedure may be employed for fair and friendly coexistence ofLAA with other operators and technologies operating in an unlicensedspectrum. LBT procedures on a node attempting to transmit on a carrierin an unlicensed spectrum may require the node to perform a clearchannel assessment to determine if the channel is free for use. An LBTprocedure may involve at least energy detection to determine if thechannel is being used. For example, regulatory requirements in someregions, for example, in Europe, may specify an energy detectionthreshold such that if a node receives energy greater than thisthreshold, the node assumes that the channel is not free. While nodesmay follow such regulatory requirements, a node may optionally use alower threshold for energy detection than that specified by regulatoryrequirements. In an example, LAA may employ a mechanism to adaptivelychange the energy detection threshold. For example, LAA may employ amechanism to adaptively lower the energy detection threshold from anupper bound. Adaptation mechanism(s) may not preclude static orsemi-static setting of the threshold. In an example a Category 4 LBTmechanism or other type of LBT mechanisms may be implemented.

Various example LBT mechanisms may be implemented. In an example, forsome signals, in some implementation scenarios, in some situations,and/or in some frequencies, no LBT procedure may performed by thetransmitting entity. In an example, Category 2 (for example, LBT withoutrandom back-off) may be implemented. The duration of time that thechannel is sensed to be idle before the transmitting entity transmitsmay be deterministic. In an example, Category 3 (for example, LBT withrandom back-off with a contention window of fixed size) may beimplemented. The LBT procedure may have the following procedure as oneof its components. The transmitting entity may draw a random number Nwithin a contention window. The size of the contention window may bespecified by the minimum and maximum value of N. The size of thecontention window may be fixed. The random number N may be employed inthe LBT procedure to determine the duration of time that the channel issensed to be idle before the transmitting entity transmits on thechannel. In an example, Category 4 (for example, LBT with randomback-off with a contention window of variable size) may be implemented.The transmitting entity may draw a random number N within a contentionwindow. The size of the contention window may be specified by a minimumand maximum value of N. The transmitting entity may vary the size of thecontention window when drawing the random number N. The random number Nmay be employed in the LBT procedure to determine the duration of timethat the channel is sensed to be idle before the transmitting entitytransmits on the channel.

LAA may employ uplink LBT at the UE. The UL LBT scheme may be differentfrom the DL LBT scheme (for example, by using different LBT mechanismsor parameters), since the LAA UL may be based on scheduled access whichaffects a UE's channel contention opportunities. Other considerationsmotivating a different UL LBT scheme include, but are not limited to,multiplexing of multiple UEs in a single subframe.

In an example, a DL transmission burst may be a continuous transmissionfrom a DL transmitting node with no transmission immediately before orafter from the same node on the same CC. A UL transmission burst from aUE perspective may be a continuous transmission from a UE with notransmission immediately before or after from the same UE on the sameCC. In an example, a UL transmission burst may be defined from a UEperspective. In an example, a UL transmission burst may be defined froman eNB perspective. In an example, in case of an eNB operating DL+UL LAAover the same unlicensed carrier, DL transmission burst(s) and ULtransmission burst(s) on LAA may be scheduled in a TDM manner over thesame unlicensed carrier. For example, an instant in time may be part ofa DL transmission burst or an UL transmission burst.

In an example embodiment, in an unlicensed cell, a downlink burst may bestarted in a subframe. When an eNB accesses the channel, the eNB maytransmit for a duration of one or more subframes. The duration maydepend on a maximum configured burst duration in an eNB, the dataavailable for transmission, and/or eNB scheduling algorithm. FIG. 10shows an example downlink burst in an unlicensed (e.g. licensed assistedaccess) cell. The maximum configured burst duration in the exampleembodiment may be configured in the eNB. An eNB may transmit the maximumconfigured burst duration to a UE employing an RRC configurationmessage.

The wireless device may receive from a base station at least one message(for example, an RRC) comprising configuration parameters of a pluralityof cells. The plurality of cells may comprise at least one cell of afirst type (e.g. license cell) and at least one cell of a second type(e.g. unlicensed cell, an LAA cell). The configuration parameters of acell may, for example, comprise configuration parameters for physicalchannels, (for example, a ePDCCH, PDSCH, PUSCH, PUCCH and/or the like).The wireless device may determine transmission powers for one or moreuplink channels. The wireless device may transmit uplink signals via atleast one uplink channel based on the determined transmission powers.

In an example embodiments, LTE transmission time may include frames, anda frame may include many subframes. The size of various time domainfields in the time domain may be expressed as a number of time unitsT^(s)=1/(15000×2048) seconds. Downlink, uplink and sidelinktransmissions may be organized into radio frames withT^(f)=307200×T_(s)=10 ms duration. In an example LTE implementation, atleast three radio frame structures may be supported: Type 1, applicableto FDD, Type 2, applicable to TDD, Type 3, applicable to LAA secondarycell operation. LAA secondary cell operation applies to frame structuretype 3.

Transmissions in multiple cells may be aggregated where one or moresecondary cells may be used in addition to the primary cell. In case ofmulti-cell aggregation, different frame structures may be used in thedifferent serving cells.

Frame structure type 1 may be applicable to both full duplex and halfduplex FDD. A radio frame is T_(f)=307200⋅T_(s)=10 ms long and maycomprise 20 slots of length T_(slot)=15360⋅T_(s)=0.5 ms numbered from 0to 19. A subframe may include two consecutive slots where subframe icomprises of slots 2i and 2i+1.

For FDD, 10 subframes are available for downlink transmission and 10subframes are available for uplink transmissions in a 10 ms interval.Uplink and downlink transmissions are separated in the frequency domain.In half-duplex FDD operation, the UE may not transmit and receive at thesame time while there may not be such restrictions in full-duplex FDD.

Frame structure type 2 may be applicable to TDD. A radio frame of lengthT_(f)=307200⋅T_(s)=10 ms may comprise of two half-frames of length153600⋅T_(s)=5 ms. A half-frame may comprise five subframes of length30720⋅T_(s)1 ms. A subframe i may comprise two slots, 2i and 2i+1, oflength T_(slot)=15360⋅T_(s)=0.5 ms

The uplink-downlink configuration in a cell may vary between frames andcontrols in which subframes uplink or downlink transmissions may takeplace in the current frame. The uplink-downlink configuration in thecurrent frame is obtained via control signaling.

An example subframe in a radio frame, “may be a downlink subframereserved for downlink transmissions, may be an uplink subframe reservedfor uplink transmissions or may be a special subframe with the threefields DwPTS, GP and UpPTS. The length of DwPTS and UpPTS are subject tothe total length of DwPTS, GP and UpPTS being equal to 30720⋅T_(s)=1 ms.

Uplink-downlink configurations with both 5 ms and 10 msdownlink-to-uplink switch-point periodicity may be supported. In case of5 ms downlink-to-uplink switch-point periodicity, the special subframemay exist in both half-frames. In case of 10 ms downlink-to-uplinkswitch-point periodicity, the special subframe may exist in the firsthalf-frame.

Subframes 0 and 5 and DwPTS may be reserved for downlink transmission.UpPTS and the subframe immediately following the special subframe may bereserved for uplink transmission.

In an example, in case multiple cells are aggregated, the UE may assumethat the guard period of the special subframe in the cells using framestructure Type 2 have an overlap of at least 1456⋅T_(s).

In an example, in case multiple cells with different uplink-downlinkconfigurations in the current radio frame are aggregated and the UE isnot capable of simultaneous reception and transmission in the aggregatedcells, the following constraints may apply. if the subframe in theprimary cell is a downlink subframe, the UE may not transmit any signalor channel on a secondary cell in the same subframe. If the subframe inthe primary cell is an uplink subframe, the UE may not be expected toreceive any downlink transmissions on a secondary cell in the samesubframe. If the subframe in the primary cell is a special subframe andthe same subframe in a secondary cell is a downlink subframe, the UE maynot be expected to receive PDSCH/EPDCCH/PMCH/PRS transmissions in thesecondary cell in the same subframe, and the UE may not be expected toreceive any other signals on the secondary cell in OFDM symbols thatoverlaps with the guard period or UpPTS in the primary cell.

Frame structure type 3 may be applicable to LAA secondary cell operationwith normal cyclic prefix. A radio frame is T_(f)=307200⋅T_(s)=10 mslong and comprises of 20 slots of length T_(slot)=15360⋅T_(s)=0.5 ms,numbered from 0 to 19. A subframe may comprise as two consecutive slotswhere subframe i comprises slots 2i and 2i+1.

The 10 subframes within a radio frame are available for downlinktransmissions. Downlink transmissions occupy one or more consecutivesubframes, starting anywhere within a subframe and ending with the lastsubframe either fully occupied or following one of the DwPTS durations.Subframes may be available for uplink transmission when LAA uplink issupported.

Some regulatory domains, e.g. Europe, may require that the transmissionof a node in a band, e.g. 5 GHz band, satisfy some criteria. Forexample, nominal channel bandwidth (e.g. defined as including the widestof frequencies including guard bands assigned to a single channel) maybe at least 5 MHz. The occupied channel bandwidth may be between 80% and100% of the declared Nominal channel bandwidth. The regulatory may alsoinclude power constraint and Power spectral density (PSD) per MHzconstraint. A PSD per MHz constraint may not be applicable to licensedspectrum transmission and this may imply that a signal which occupies asmall portion of the bandwidth may not be transmitted at a maximumavailable power at the UE due to the PSD and occupied bandwidthconstraints.

In an example, a wireless device may be configured with a plurality ofcells of different cell types. A base station may transmit to a wirelessdevice one or more message comprising configuration parameters of aplurality of cells. For example, different cell types may be cellsoperating on different frequency bands, for examples cells of a firsttype may operate in a first frequency band and cells of a second typemay operate in a second frequency band. For example, different celltypes may be cells operating according to different criteria (e.g.regulatory rules, transceiver design, and/or technology limitation). Forexamples cells of a first type may operate according to a first criteriaof and cells of a second type may operate in according to a secondcriteria. For examples cells of a first type may operate according to afirst technology of and cells of a second type may operate in accordingto a second technology.

In an example, uplink channels in an LAA cell, such as PUSCH, PUCCH,PRACH and/or SRS, may not be transmitted at high power if they do notoccupy a wide bandwidth, e.g., entire bandwidth. A signal transmitted inuplink LAA may need to meet the bandwidth occupancy and/or allowtransmission at high power by meeting the PSD per MHz constraint.Interleaved transmission may be employed on the uplink which spans thewhole bandwidth for a carrier. An interleaved uplink may allow frequencydivision multiplexing of several uplink transmissions which is one ofthe design targets for LAA.

In an example, RB interleaved (multi-clustered) transmission, theminimum transmission unit may be one interlace, a set of RBs uniformlyspaced in frequency to span a bandwidth. For example, in a 20 MHz systemwith 100 RBs, the ith interlace may be comprised of 10 RBs {i, i+10,i+20, . . . , i+90}. For example, a 20 MHz system may have 10interlaces. An interlace may have with 10 RBs in the uplink which may beshared among the users.

An example interleaved structure may allow a UE to occupy a widebandwidth with at least one RB and may use power boosting to transmit athigh power in the unlicensed spectrum thus improving coverage.Transmission at high power may silence more interferers thantransmission at lower power and may improve the reception at the eNBreceiver and may satisfy the 80% bandwidth occupancy requirement. In anexample, the interleaved structure may also be applied to other uplinkchannels such as PUCCH and/or PRACH. An RB interleaved transmission with10 RBs uniformly spaced in frequency may be a basic unit of resourceallocation on the uplink for 20 MHz and/or 10 MHz eLAA SCell.

By RB level multi-cluster PUSCH transmission, regulatory requirements onthe occupied bandwidth may be met if the PUSCH transmission is spread into a sufficiently large bandwidth. For example, ETSI requirement ofpower spectral density (shown below) may be satisfied. According to ETSIregulation, the RF output power and power spectral density (PSD) may beconstrained in certain unlicensed bands. In addition to limitingPCMAX/PCMAX,C to mean EIRP, LAA UE may also limit the PSD. ULtransmission power may be configured to meet the requirement of maximumtransmission power and/or PSD.

In an example, transmit Power Control (TPC) may enable an averagereduction in the aggregated transmission power by at least 3 dB (5 dBfor FWA) compared with a maximum permitted transmission power. TCP maynot be required for channels within the band 5150-5250 MHz. Without TPC,a highest permissible average EIRP (density) may be reduced by 3 dB.

According to the regulatory requirements of PSD, transmit power may beuniformly distributed in a bandwidth, in order to reduce the PSD ofsub-bands while utilizing the UE total transmit power. In an example,considering of a defined 1 MHz resolution bandwidth for PSD testing,PUSCH signal power may be equally distributed in each 1MHz bandwidthsuch that a maximum 23 dBm UE Tx power may be fully utilized, withoutviolating the PSD requirement, e.g. maximum 10 dBm per 1 MHz sub-band.It may be allowed to distribute the PUSCH transmission in 1 MHz subbandsat least when the maximum Tx power is utilized, 20 may be considered asthe maximum number of PUSCH clusters. In case of reduced Tx power (e.g.the maximum Tx power is not fully utilized), number of PUSCH clustersmay be reduced (e.g. 10 clusters). The actual allocated number ofclusters may be decided by the eNB scheduler. In an example, for RBlevel frequency distributed structure with 10 interlaces, if maximum UETx power is not less than 20 dBm, 20 clusters corresponding to at least2 interlaces evenly distributed in frequency may be applied.

To meet regulatory requirements of PSD, PUSCH transmit power may beequally distributed to an allocated transmission bandwidth. Examplenumber of PUSCH cluster 20 may be considered in order to utilize UE Txpower while meeting the regulation on PSD. For example, multiplexing ofmultiple UE PUSCH with different traffic needs in one UL subframe may besupported for eLAA.

In some countries, maximum PSD (power spectral density) in an unlicensedband may be limited by regulation. PSD of a UE's uplink transmission maybe restricted to be compliant with regulation. In an example, UE'suplink transmission power may be adjusted to be compliant with regionalregulations on maximum PSD. In an example, maximum uplink PSD may beconfigured by RRC for an LAA cell. Configuration of maximum uplinktransmission power such as Pcmax and/or Pcmax,c may be implemented.

In an example LTE network, once the required QoS is achieved at eNB, ULtransmitter power may be reduced to reduce inter-cell interferenceand/or increase battery life of a UE. In an LAA cell, if a UE with lowtransmitting power is not detected by a WIFI AP adjacent to an eNB, theWIFI AP may transmit during the UE transmission such that the receptionperformance at eNB may be degraded. In an example, a hidden node mayexist, where a UE UL transmission performance may be reduced by hiddennode WIFI AP and the two devices may not be able to listen to each otherand therefore transmit simultaneously.

In an example implementation, an eNB may identify the presence andpotentially a signal strength of neighbor nodes (e.g. WIFI node)according to network measurement and/or UE measurement reports. An eNBmay decide the transmission power target of the UE to enable that areceived signal strength of a UE signal at the WIFI AP location tobecome higher than the CCA threshold, e.g. −62 dBm. The Tx poweradjustment may be achieved by eNB signals the proper Po value of the UEpower control formula. UL power control mechanism on an LAA cell may beemployed to mitigate a hidden node problem.

In legacy LTE, a UE close to an eNB may transmit at low power for uplinktransmission, which may not be efficient for the UL LBT operation. UE'suplink transmission power may be configured to be more than a certainlevel of minimum transmission power. In an example, a minimumtransmission power may be configured for a UE employing one or more RRCparameters for LAA SCell.

In Rel-13 LAA, the CCA energy detection threshold for DL LBT may bedetermined by the presence of other technologies on a long-term basis,set maximum eNB output power for the carrier, and channel bandwidth. Inan example, a similar threshold adaptation rule may be used for UL LBT.For example, maximum eNB output power is replaced by the configuredmaximum output power for that carrier (PCMAX,c) and/or configured upperbound of transmission power (PEMAX, c). The UL LAA LBT is ratherconservative if the CCA threshold depends on PCMAX,c or PEMAX, c. Thechannel access probability of an LAA UE may be reduced.

An actual UL transmit power (e.g. instead of PCMAX,c or PEMAX, c) may beimplemented to determine the CCA threshold. In an example, an eNB maymake a choice between higher channel access opportunity and higher SINR.For example, on a loaded unlicensed carrier, lower UL transmission poweris configured to increase the probability to access the channel withhigher CCA threshold.

A UE may reduce the UL transmission power to exchange for a higher CCAthreshold. A UE may drop the UL transmission when the UL transmissionpower derived from the detected energy level of CCA is less than thelower bound configured by eNB.

The energy detection threshold for UL LBT may be similar to that for DLLBT. In an example instead of the maximum transmission power, otheralternatives may be considered: Use the PCMAX,c or PEMAX, c, use theactual UL transmit power configured by eNB, and/or use the reduced ULtransmit power by UE.

In UL power control operation, the upper bound of UL transmission poweris constrained by PCMAX,C and the total configured maximum output powerPCMAX, when the UE is configured with more than one CC. PCMAX may varywith the number of aggregated UL CCs. PCMAX,C also depends on the numberof PRBs together with the modulation order for intra-band CA. In thecase of CA, UE may get the information of scheduled UL transmissions bydecoding UL grants for these scheduled UL CCs at almost the same time.The scheduled UL transmissions may be transmitted. A UE may determinethe maximum transmit power, and the UE may scale the power of some ULchannels/signals with lower priority if it is in power-limited case.There would be several milliseconds (between the subframe UE receivesthe UL grant and the subframe UE transmits UL channels/signals) toprepare the bits and UL power for the scheduled UL transmissions. In thecase of Dual-connectivity, when the UL CCs are not well synchronized, UEmay receive the UL grants from one eNB earlier while from the other eNBlater, e.g. with up to 1 ms delay between MeNB and SeNB. In that case,the processing time is reduced by at most 1 ms, if UE starts preparingthe UL transmission associated with earlier transmission after thereception of UL grants associated with later transmission. Theprocessing time may not be enough. A “non-look-ahead” behaviour may bespecified that the transmission power of earlier UL transmission isdetermined without the consideration of later UL transmission.

In CA-based LAA system, UE may decode UL grants for scheduled ULtransmissions at the same time. A UE may not know which UL CCs out ofscheduled UL CCs may be transmitted, because the scheduled ULtransmission on unlicensed Scells may be dropped due to the failure ofLBT. In the case the number of UL CCs finally transmitted is differentthan that of scheduled, the PCMAX,C and PCMAX may change. It may not bepossible for UE to prepare UL transmission power according to PCMAX,Cand PCMAX based on the real transmission, since the LBT result is knownseveral microseconds before the transmission. A UE may determine thetransmission power according to the scheduled UL CCs, no matter some ofthese UL CCs may be transmitted or not. UE may suffer power waste whensome UL transmissions on unlicensed Scells are dropped. Especially whenthe power-limited case is identified with the assumption that scheduledUL CCs are to be transmitted, UE reserves power for some UL transmissionwhich is finally dropped while reduces the power for some ULtransmission which is definitely to be transmitted. For example, thepower of PUSCH on licensed Pcell/Scells is scaled to reserve some powerfor PUSCH on unlicensed cells, but LBT is failed. It results in poorpower efficiency. Besides, it would be undesirable that best-efforttransmission on unlicensed Scells affects the traffic with higher QoSrequirement, which is typically carried by licensed CCs.

In an example, UL transmission power may be determined according toscheduled PUSCH transmission. A power allocation mechanism betweenlicensed and unlicensed CCs may be implemented for when a UE is powerlimited. The mechanism may improve the power efficiency as well asprovides an improved performance for higher QoS/priority traffic. Incase of maximum transmission power limitation, handling of transmissionson multiple carriers including LAA SCell may be decided. Transmissionson LAA SCell may be deprioritized to the transmissions on licensedcarriers.

In legacy LTE, power headroom indicates the difference between themaximum transmit power and the current transmit power. An eNB maydetermine the UL resource allocation based on the PHR. There are twotypes of PHR, virtual PHR and real PHR. The virtual PHR may be reportedwhen there is no UL transmission on the corresponding UL CC, e.g., whenan eNB does not schedule the UL transmission in some subframes. A realPHR is reported when there is UL transmission, which is based on a realtransmission. Uplink power headroom for PHR (power headroom report) in asubframe may calculated based on the calculated transmission power on acarrier if PUSCH or PUCCH is transmitted in a carrier. Otherwise, powerheadroom is calculated based on the virtual transmission power of PUSCHor PUCCH.

In an LAA cell, the UL transmission is subject to LBT, and a scheduledUL transmission may be dropped if the channel is busy. A UE may estimatethe power headroom with the assumption of a real transmission, e.g.,received UL grant. The type of PHR may be determined by the schedulinginformation of UL transmission instead of real transmission. A reportedPCMAX,C in PHR is also determined based on a scheduled UL transmissioninstead of real transmission.

Uplink transmission on an LAA SCell may be dropped within a short time(e.g. few micro seconds) before the subframe boundary due to LBTfailure. It may not be possible to modify the PHR information encoded ina PUSCH reflecting the LBT results of other carriers. In an example, PHRin a subframe may be calculated reflecting the uplink transmissionsscheduled in LAA cell in the subframe regardless whether actualtransmission is performed or not. PHR for an LAA cell may be generatedaccording to a scheduled UL transmission indicated by an UL grant.

LTE release-13 UL power control mechanisms may be enhanced to supporttransmission of signals in the uplink of a plurality of cells ofdifferent cell types (e.g. licensed cells and LAA cells). LTE UL powercontrol may reduce a UE transmission power as long as the receptionperformance at eNB satisfies the requirement. The eNB may transmit TPCfor uplink transmission. In an example, uplink transmission in an LAAcell with LBT operation in the LAA cell, a UE transmission power may beemployed by other wireless devices within certain coverage to preventuplink transmission by other nodes and creating interference.

In an example, uplink power control may reduce UL transmit power to arelatively low level. Uplink transmit power of below a threshold may notbe suitable for LAA operation on an unlicensed carrier. Enhancement ofUL power control algorithms suitable for LBT operation may beconsidered. In an example embodiment, a UE's minimum transmit power maybe configured (via one or more parameters in one or more RRC message) toreduce the possibility of other UEs detecting the channel free andstarting transmission and interfering with the UE. A UE may beconfigured to transmit above a minimum transmit power value on an LAAcell. In an example embodiment, this may be enabled even if the eNB isable to detect its signal at below the minimum value.

In an example, in an LAA cell, a maximum transmit power spectral densitymay be limited, e.g. the power limit may depend on transmissionbandwidth. Maximum allowed transmission power may depend on transmissionbandwidth. The power control in the current LTE systems may limitmaximum total output power of a UE via configurable maximum transmitpower PCMAX independent of transmission bandwidth (the number of RBsused for uplink transmission). The current LTE systems do not provide acapability for configuration of maximum power depending based on theuplink transmission bandwidth (the number of RBs in an uplinktransmission). Enhancements may be considered to control the maximumtransmit power spectral density of a UE in an unlicensed band.Mechanisms may be implemented to allocate UEs transmit power todifferent cells including licensed cell and LAA cells, e.g. when the UEis power limited.

In an example embodiment, a UE may calculate transmit power for PRACH,PUSCH, PUCH, and/or SRS in the uplink according to a power controlformula. The calculations of uplink transmit power for a signal mayemploy uplink power calculations in release 13 with additionalenhancements to improve uplink transmission power for different celltypes.

Uplink transmission power of PUSCH, PUCCH, and/or SRS may be adjusted(scaled down) when uplink transmit power of serving cells exceed maximumtransmit power of the UE. For example, In FIG. 11, powers may becalculated for uplink signals (e.g. PUSCH and/or PUCCH) on carriers Band E in subframe n+1. If a total maximum calculated transmit power doesnot exceed the max transmit power of the UE, the UE may transmit signalson carriers B and E according to a calculated power. If the totalmaximum calculated transmit power exceed the max transmit power of theUE, the UE may transmit signals on carriers B and E according to apredefined rule by adjusting (scaling) the transmission power. In anexample, a UE may drop one or more signals, and transmit one or moreother signals to meet the power requirements. In an example embodiment,SRS signals may be dropped if SRS signals cannot be transmitted inparallel with PUSCH and/or PUCCH signals in a cell group (MCG, SCG).

Example power control formulas for calculating the power of PUSCH, PUCCHand SRS in different scenarios are presented below. In an example, someadditional enhancements may be made to power control mechanisms toimprove power control efficiency in an LAA cell.

In an example implementation, the setting of the UE Transmit power for aPhysical Uplink Shared Channel (PUSCH) transmission may be determined asfollows.

If the UE transmits PUSCH without a simultaneous PUCCH for the servingcell C, then the UE transmit power P_(PUSCH,c)(i) for PUSCH transmissionin subframe i for the serving cell C may be given by

${P_{{PUSCH},c}(i)} = {\min {\begin{Bmatrix}{{P_{{PCMAX},c}(i)},} \\{{10\; {\log_{10}( {M_{{PUSCH},c}(i)} )}} + {P_{{O\_ PUSCH},c}(j)} + {{\alpha_{c}(j)} \cdot {PL}_{c}} + {\Delta_{{TF},c}(i)} + {f_{c}(i)}}\end{Bmatrix}\lbrack {dBm}\rbrack}}$

If the UE transmits PUSCH simultaneous with PUCCH for the serving cellC, then the UE transmit power P_(PUSCH,c)(i) for the PUSCH transmissionin subframe i for the serving cell c may be given by

${P_{{PUSCH},c}(i)} = {\min {\begin{Bmatrix}{{10{\log_{10}( {{{\hat{P}}_{{CMAX},c}(i)} - {{\hat{P}}_{{PUCCH},c}(i)}} )}},} \\{{10{\log_{10}( {M_{{PUSCH},c}(i)} )}} + {P_{{O\; \_ \; {PUSCH}},c}(j)} + {{\alpha_{c}(j)} \cdot}} \\{{PL}_{c} + {\Delta_{{TF},c}(i)} + {f_{c}(i)}}\end{Bmatrix}\lbrack{dBm}\rbrack}}$

If the UE is not transmitting PUSCH for the serving cell c, for theaccumulation of TPC command received with DCI format 3/3A for PUSCH, theUE may assume that the UE transmit power P_(PUSCH,c)(i) for the PUSCHtransmission in subframe i for the serving cell C may be computed by

P _(PUSCH,c)(i)=min{P _(CMAX,c)(i),P _(O) _(_) _(PUSCH,c)(1)+α_(c)(1)⋅PL_(c) +f _(c)(i)}[dBM]

In an example implementation, if serving cell c is the primary cell, forPUCCH format 1/1a/1b/2/2a/2b/3, the setting of the UE Transmit powerP^(PUCCH) for the physical uplink control channel (PUCCH) transmissionin subframe i for serving cell c may be determined by

${P_{PUCCH}(i)} = {\min {\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\{P_{0\_ \; {PUCCH}} + {PL}_{c} + {h( {n_{CQI},n_{HARQ},n_{SR}} )} +} \\{{\Delta_{F\; \_ \; {PUCCH}}(F)} + {\Delta_{TxD}( F^{\prime} )} + {g(i)}}\end{Bmatrix}\lbrack{dBm}\rbrack}}$

If serving cell c is the primary cell, for PUCCH format 4/5, the settingof the UE Transmit power P^(PUCCH) for the physical uplink controlchannel (PUCCH) transmission in subframe i for serving cell c may bedetermined by

${P_{PUCCH}(i)} = {\min {\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\{P_{0\_ \; {PUCCH}} + {PL}_{c} + {10{\log_{10}( {M_{{PUCCH},c}(i)} )}} +} \\{{\Delta_{{TF},c}(i)} + {\Delta_{F\; \_ \; {PUCCH}}(F)} + {g(i)}}\end{Bmatrix}\lbrack{dBm}\rbrack}}$

If the UE is not transmitting PUCCH for the primary cell, for theaccumulation of TPC command for PUCCH, the UE may assume that the UEtransmit power P_(PUCCH) for PUCCH in subframe i is computed by

P _(PUCCH)(i)=min{P _(CMAX,c)(i),P _(O) _(_) _(PUCCH) +PL _(c)+g(i)}[dBM]

In an example implementation, the setting of the UE Transmit powerP_(SRS) for the SRS transmitted on subframe i for serving cell c may bedetermined by

P _(SRS,c)(i) min{P _(CMAX,c)(i),P _(SRS) _(_) _(OFFSET,c)(m)+10log₁₀(M_(SRS,c))+P_(O) _(_) _(PUSCH,c)(j)+α_(c)(j)⋅PL _(c)+f _(c)(i)}[dBM]

There is a need to determine the transmit power of signals in an LTEnetwork when cell of different types are configured/activated and a UEis power limited. Example embodiments present a mechanism fordetermining the power of uplink signals in a UE. There is a need todevelop mechanisms for determining the transmit power of uplink signalsin different cell types.

In an example implementation and when one cell type is configured andactivated, if the UE is not configured with an SCG or a PUCCH-SCell, andif the total transmit power of the UE would exceed {circumflex over(P)}_(CMAX)(i), the UE may scale {circumflex over (P)}_(PUSCH,c)(i) forthe serving cell c in subframe i such that the condition

${\sum\limits_{c}^{\;}{{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq ( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)}} )$

is satisfied where {circumflex over (P)}_(PUSCH,c)(i) is the linearvalue of P_(PUSCH)(i), {circumflex over (P)}_(PUSCH,c)(i) is the linearvalue of P_(PUSCH,c)(i), {circumflex over (P)}_(CMAX)(i) is the linearvalue of the UE total configured maximum output power P_(CMAX) insubframe i and w(i) is a scaling factor of {circumflex over(P)}_(PUSCH,c)(i) for serving cell c where 0≤w(i)≤1. In case there is noPUCCH transmission in subframe i {circumflex over (P)}_(PUSCH)(i)=0.

If the UE is not configured with an SCG or a PUCCH-Scell, and if the UEhas PUSCH transmission with UCI on serving cell j and PUSCH without UCIin any of the remaining serving cells, and the total transmit power ofthe UE would exceed {circumflex over (P)}_(CMAX)(i), the UE scales{circumflex over (P)}_(PUSCH,c)(i) for the serving cells without UCI insubframe i such that the condition

${\sum\limits_{c \neq j}^{\;}{{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq ( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{{PUSCH},j}(i)}} )$

is satisfied where {circumflex over (P)}_(PUSCH,j)(i) is the PUSCHtransmit power for the cell with UCI and w(i) is a scaling factor of{circumflex over (P)}_(PUSCH,c)(i) for serving cell c without UCI. Inthis case, no power scaling is applied to {circumflex over(P)}_(PUSCH,c)(i) unless

${\sum\limits_{c \neq j}^{\;}{{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} = 0$

and the total transmit power of the UE still would exceed {circumflexover (P)}_(CMAX)(i).

For a UE not configured with a SCG or a PUCCH-SCell, note that w(i)values are the same across serving cells when w(i) >0 but for certainserving cells w(i) may be zero.

If the UE is not configured with an SCG or a PUCCH-SCell, and if the UEhas simultaneous PUCCH and PUSCH transmission with UCI on serving cell jand PUSCH transmission without UCI in any of the remaining servingcells, and the total transmit power of the UE would exceed {circumflexover (P)}_(CMAX)(i), the UE obtains {circumflex over (P)}_(PUSCH,c)(i)according to

P̂_(PUSCH, j)(i) = min (P̂_(PUSCH, j)(i), (P̂_(CMAX)(i) − P̂_(PUCCH)(i)))  and${\sum\limits_{c \neq j}^{\;}{{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq ( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)} - {{\hat{P}}_{{PUSCH},j}(i)}} )$

For a BL/CE UE configured with CEModeA, if the PUSCH is transmitted inmore than one subframe i0,i1, . . . , iN−1 where i0<i1< . . . <iN−1, thePUSCH transmit power in subframe ik, k=0, 1, . . . , N−1, is determinedby P_(PUSCH,c)(i_(k))=P_(PUSCH,c)(i₀). For a BL/CE UE configured withCEModeB, the PUSCH transmit power in subframe ik is determined byP_(PUSCH,c)(i_(k))=P_(CMAX,c)(i₀).

In an example embodiment, different power priorities may be assigned totransmission power of different signals in a CG. In an example, thefollowing power priorities may be considered:

In an example embodiment, signals transmitted on a cell of a second type(e.g. an LAA cell) may be assigned a lower priority compared withsignals transmitted on a cell of a first type (e.g. licensed cells). Forexample, the following power priorities may be considered: (_L1 denotessignals on a cell of a first type and _L2 denotes signals on a cell of asecond type).

PRACH>PUCCH>PUSCH_L2 with UCI>PUSCH_L1UCI>PUSCH_L2>PUSCH_L1

In an example, parallel PRACH transmission on a cell of a first type anda cell of a second type (e.g. licensed and LAA cells) may not besupported. In an example, PUCCH may be configured on a cell of a firsttype (e.g. licensed cells) and no PUCCH may be configured on a cell of asecond type (e.g. an LAA cell).

Example power priority may provide a higher transmit power priority tosignals transmitted on cells of a second type (e.g. LAA cells). Forexample, this may enable reserving LAA cells and accessing LAA channelswith a higher probability. For example, successful access to LAA cellsmay require transmission with higher power. Access to LAA cells requiresLBT and LAA cells may have a higher interference. Low signaltransmission power on LAA cells may substantially increase accessfailure. There is no need for LBT on licensed cells and licensed cellsmay be less sensitive to power reduction. For example, when PUSCH,jtransmits PUSCH_L1 with UCI, the PUSCH_L2 UCI signal power may beadjusted so that:

P_(PUSCH,j)(i)≤({circumflex over (P)}_(CMAX)(i)-{circumflex over(P)}_(PUCCH)(i)-{circumflex over (P)}_(PUSCH) _(_) _(UCI) _(_) _(L2)(i))

PUSCH_L1 signal power may be adjusted based on:

${\sum\limits_{c \neq j}^{\;}{{w(i)} \cdot {{\hat{P}}_{{{PUSCH}\; \_ \; L\; 2},c}(i)}}} \leq ( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)} - {{\hat{P}}_{{PUSCH},j}(i)} - {P_{{PUSCH}\; \_ \; {UCI}\; \_ \; L\; 2}(i)}} )$

PUSCH_L2 signal power may be adjusted based on:

${\sum\limits_{c \neq j}^{\;}{{w(i)} \cdot {{\hat{P}}_{{{PUSCH}\; \_ \; L\; 1},c}(i)}}} \leq ( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)} - {{\hat{P}}_{{PUSCH},j}(i)} - {P_{{PUSCH}\; \_ \; {UCI}\; \_ \; L\; 2}(i)} - {\sum\limits_{c \neq j}^{\;}{\cdot {{\hat{P}}_{{{PUSCH}\; \_ \; L\; 2},c}(i)}}}} )$

In an example embodiment, the priorities may be managed based onassigning different weighting factors, w(i), to cells of a first typeand cell of a second type. For example, a first type cell power may beadjusted employing, wl1(i) factor. A second type cell power may beadjusted employing wl2(i) factor.

For example,

${{\sum\limits_{c \neq j}^{\;}{{wl}\; 2{(i) \cdot {{\hat{P}}_{{{PUSCH}\; \_ \; L\; 2},c}(i)}}}} + {\sum\limits_{c \neq j}^{\;}{{wl}\; 1{(i) \cdot {{\hat{P}}_{{{PUSCH}\; \_ \; L\; 1},c}(i)}}}}} \leq ( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)} - {{\hat{P}}_{{PUSCH},j}(i)} - {P_{{PUSCH}\; \_ \; {UCI}\; \_ \; L\; 2}\text{?}\text{?}\text{indicates text missing or illegible when filed}}} $

In an example, a similar method may be applied to power calculations ofPUSCH transmission with UCI.

In an example embodiment, an RRC message may comprise one or moreparameters that are employed for calculation of wl1(i) factor and wl2(i)factor. For example, an offset may be configured for the relative weightfactors on cells of a first type and cells of a second type (e.g.licensed and LAA cells).

In an example embodiment, SRS signals may be assigned a lower powerpriority compared with other signals, e.g. PUCCH, PRACH, and/or PUSCH.

In Release-13, a UE not configured with multiple TAGs may not transmitSRS in a symbol whenever SRS and PUSCH transmissions happen to overlapin the same symbol in the same CG (MCG or SCG). Such mechanism mayincrease SRS dropping probability.

Enhanced mechanisms introduced in example embodiments of the inventionreduces SRS dropping probability. In many instances SRS signals aretransmitted in parallel with PUSCH and/or other signals (e.g. PUCCH,reservation signals, other SRSs) in parallel in the same Cell Group (MCGand/or SCG).

In many scenarios, the UE may not have enough transmission power totransmit SRS signals and PUSCH and/or other signals in parallel.Enhanced power control mechanisms are required to enable enhanced SRStransmission mechanisms when UE is power limited.

FIG. 12 and FIG. 13 illustrate examples, wherein SRS signals aretransmitted in parallel with PUSCH and/or other signals and/orreservation signal. Many different combinations are possible. In anexample implementation, transmission of reservation signals (R) may notbe implemented in the UE. In another example implementation,transmission of reservation signals may be implemented in the UE.

In an example embodiments transmission powers may be assigned differenttransmission priorities. Assigning different transmission priorities todifferent signals in an enhanced SRS transmission mechanism may simplifythe power management in the UE. In an example embodiment, there may bemany implementations for handling signals with lower priorities, whenthe UE does not have enough transmission power. In one exampleembodiment, signals with lower priorities may be dropped when the UEdoes not have enough transmission power. In an example embodimentsignals with lower priorities may be adjusted (scaled down) when the UEdoes not have enough transmission power. In an example embodiment, someof the signals with lower priorities may be dropped, and some others maybe adjusted (scaled down) when the UE does not have enough transmissionpower.

For simplicity we may consider one CG in the following exampleembodiments. When DC or PUCCH CGs are configured, the UE may combine theexample embodiments in a CG along with CG power control mechanismsdisclosed in the specification.

In an example embodiment, SRS transmission power may be assigned a lowerpriority compared with PUCCH, and PUSCH and R signal transmissions. Inan example embodiment, there may be many implementations for handlingsignals with lower priorities, when the UE does not have enoughtransmission power. In one example embodiment, SRS may be dropped whenthe UE does not have enough transmission power. In an example embodimentSRS power may be adjusted (scaled down) when the UE does not have enoughtransmission power. In an example embodiment, some of the SRS signalswith lower priorities may be dropped, and some other SRSs may beadjusted (scaled down) if needed when the UE does not have enoughtransmission power. For example, SRS in licensed bands or unlicensedbands may be dropped. In another example, a first type of SRS may bedropped and a second type of SRS may be transmitted and/or scaled downif needed.

In an example embodiment, SRS transmission power may be assigned a lowerpriority compared with PUCCH, and PUSCH signal transmissions, but not Rsignal transmissions. R signals transmission power may be assigned alower priority compared with SRS. R signal transmission power may bescaled down or R signal may be dropped when the UE does not have enoughtransmit power.

The UE may calculate remaining power for SRS transmission according tothe defined priorities.

In an example embodiment, when the UE does not have enough power totransmit SRS and PUSCH in parallel in multiple cells, the UE may dropSRS transmissions across the cells in a CG. This mechanism may be simplebut may increase the probability of SRS dropping in the UE.

In an example embodiment, when the UE does not have enough power totransmit SRS and PUSCH in parallel in multiple cells, the UE mayconsider different priorities for SRS signals in cells of a first typeand cells of a second type (e.g. LAA cells and licensed cells).

For example, the UE may consider higher priority for SRS transmission oncells of a second type (e.g. LAA cells) compared with cells of a firsttype (e.g. licensed cells). For example, the UE may drop SRStransmissions across cells of a first type (e.g. licensed cells) in aCG. The UE may transmit SRS transmissions across cells of a second type(e.g. LAA cells) in a CG if it has sufficient power. If the UE does nothave sufficient power to transmit SRS on only cells of a second type(e.g. LAA cells), then the UE may drop (or scale down power of) SRStransmission on cells of a second type (e.g. LAA cells).

For example, the UE may consider higher priority for SRS transmission oncells of a first type (e.g. licensed cells) compared with cells of asecond type (e.g. LAA cells). For example, the UE may drop SRStransmissions across cells of a second type (e.g. LAA cells) in a CG.The UE may transmit SRS transmissions across cells of a first type (e.g.licensed cells) in a CG if it has sufficient power. If the UE does nothave sufficient power to transmit SRS on only cells of a first type(e.g. licensed cells), then the UE may drop (or scale down power of) SRStransmission on cells of a first type (e.g. licensed cells).

In an example embodiment, SRS signals that are transmitted in a subframeof a serving cell that does not include PUSCH transmission may beprioritized differently from SRS signals that are transmitted in asubframe of a serving cell that includes transmission of PUSCH. Forexample, this may allow the UE to drop if SRS is transmitted alonewithout PUSCH in the subframe, when the UE is power limited, while theUE transmits SRS in a cell with PUSCH in the subframe of the cell (if UEhas enough power). In another example, this may allow the UE to drop ifSRS is transmitted with PUSCH in the subframe, when the UE is powerlimited, while the UE transmits SRS in a cell without PUSCH in thesubframe of the cell (if UE has enough power).

In an example embodiment, SRS signals adjacent to PUSCH transmission (inthe same or subsequent subframe) may be prioritized differently from SRSsignals that are not adjacent to PUSCH. For example, this may allow theUE to drop if SRS is transmitted alone without PUSCH, when the UE ispower limited, while the UE transmits SRS adjacent with PUSCH in thecell (if UE has enough power). In another example, this may allow the UEto drop if SRS adjacent PUSCH in the subframe, when the UE is powerlimited, while the UE transmits SRS that is not adjacent to PUSCH in thecell (if UE has enough power).

In an example embodiment, a UE may consider power scaling for SRStransmission in addition to the above priorities. This may allow the UEto transmit SRSs when adjusted (scaled down) transmission power when SRStransmission at the calculated power exceeds maximum transmission power.Instead of dropping SRSs of certain category, the UE may scale down thepower of SRS transmission of a category. The lower category of SRS maystill be dropped (if there is not enough power to transmit the SRS). Insome embodiments different SRS transmissions may be considered of thesame power category and/or priority.

In legacy LTE systems, a maximum allowable transmit power is notdependent on a number of configured and activated cells. In an exampleembodiment, a maximum allowable transmit power in a UE may depends onwhether cells of a second type (e.g. LAA cells) are configured andactivated. In an example embodiment, cells of a second type may followdifferent regulatory requirements related to transmit power. Forexample, a UE that does not transmit on any activated cells of a secondtype, may have a maximum transmit power P_cmax. When the UE isconfigured and transmits signals on cells of a second type, it may beallowed to transmit additional power exceeding P_cmax on activatedlicensed and cells of a second type. Different implementation mechanismsmay be employed. An eNB may transmit one or more RRC messages comprisingconfiguration parameters of cells. Configuration parameters may compriseone or more parameters indicating a first maximum allowable transmitpower when cells of a first type (e.g. licensed cell) are configured andactivated and a second maximum allowable transmit power when cell of afirst type and cells of a second type are configured and activated. Inan example, maximum allowable transmit powers may be computed based onone or more parameters by a UE.

In an example, a maximum allowable transmit power when licensed cellsare configured and activated may be P1. A maximum allowable transmitpower when licensed and cells of a second type (e.g. LAA cells) areconfigured and activated may be P2. In an example, a power P2-P1 may beemployed by LAA cells, and a power P1 may be employed for uplinktransmission on licensed cells.

In an example, a maximum allowable transmit power when cells of a firsttype (e.g. licensed cells) are configured and activated may be P1. Amaximum allowable transmit power when licensed and cells of a secondtype (e.g. LAA cells) are configured and activated may be P2. In anexample, a power P>P2-P1 may be employed by cells of a second type, anda power P may be employed by cells of a first type in a way that totalpower is below P2. Power allocation mechanisms among cells of a firsttype and cells of a second type may be configured by RRC and may bedetermined by UE power control mechanisms. In an example, a portion ofpower budget may be shared by both signals transmitted on one or morecells of a first type and one or more cells of a second type accordingto certain power priority allocated to different signals and/or cells.

In an example embodiment different power priorities may be assigned tosignals of different channels. When a total transmit power exceeds anallowable transmit power, a UE may adjust transmit power of uplinksignals according to a power priority. For example, the following powerpriority may be considered when transmitting signals in parallel:

PRACH>PUCCH>PUSCH with UCI>PUSCH>SRS

In an example embodiment, the power priority of signals transmitted onan LAA cell may depend on whether the signal is transmitted at abeginning of an uplink burst. The first TB and/or SRS transmitted in abeginning of an uplink burst may have a higher power priority comparedwith some other signals (e.g. PUSCH and/or SRS). The initialtransmission may enable a UE access an LAA channel. If a firsttransmission is dropped, the probability of the UE to access the channelin one or more subsequent LBT opportunity or subframe may decrease.

In an example embodiment, when a UE is power limited, a first SRS signaltransmitted on a cell may have a higher power priority than relative toother signals (e.g. PUSCH and/or SRS) of other cells compared with asecond SRS transmitted later during the uplink burst. I an exampleembodiment, when a UE is power limited, a first PUSCH signal transmittedon a cell may have a higher power priority relative to other signals(e.g. PUSCH and/or SRS) of other cells compared with a second PUSCHtransmitted later during the uplink burst.

In this specification, “a” and “an” and similar phrases are to beinterpreted as “at least one” and “one or more.” In this specification,the term “may” is to be interpreted as “may, for example.” In otherwords, the term “may” is indicative that the phrase following the term“may” is an example of one of a multitude of suitable possibilities thatmay, or may not, be employed to one or more of the various embodiments.If A and B are sets and every element of A is also an element of B, A iscalled a subset of B. In this specification, only non-empty sets andsubsets are considered. For example, possible subsets of B={cell1,cell2} are: {cell1}, {cell2}, and {cell1, cell2}.

In this specification, parameters (Information elements: IEs) maycomprise one or more objects, and each of those objects may comprise oneor more other objects. For example, if parameter (IE) N comprisesparameter (IE) M, and parameter (IE) M comprises parameter (IE) K, andparameter (IE) K comprises parameter (information element) J, then, forexample, N comprises K, and N comprises J. In an example embodiment,when one or more messages comprise a plurality of parameters, it impliesthat a parameter in the plurality of parameters is in at least one ofthe one or more messages, but does not have to be in each of the one ormore messages.

Many of the elements described in the disclosed embodiments may beimplemented as modules. A module is defined here as an isolatableelement that performs a defined function and has a defined interface toother elements. The modules described in this disclosure may beimplemented in hardware, software in combination with hardware,firmware, wetware (i.e hardware with a biological element) or acombination thereof, all of which are behaviorally equivalent. Forexample, modules may be implemented as a software routine written in acomputer language configured to be executed by a hardware machine (suchas C, C++, Fortran, Java, Basic, Matlab or the like) or amodeling/simulation program such as Simulink, Stateflow, GNU Octave, orLabVIEWMathScript. Additionally, it may be possible to implement modulesusing physical hardware that incorporates discrete or programmableanalog, digital and/or quantum hardware. Examples of programmablehardware comprise: computers, microcontrollers, microprocessors,application-specific integrated circuits (ASICs); field programmablegate arrays (FPGAs); and complex programmable logic devices (CPLDs).Computers, microcontrollers and microprocessors are programmed usinglanguages such as assembly, C, C++ or the like. FPGAs, ASICs and CPLDsare often programmed using hardware description languages (HDL) such asVHSIC hardware description language (VHDL) or Verilog that configureconnections between internal hardware modules with lesser functionalityon a programmable device. Finally, it needs to be emphasized that theabove mentioned technologies are often used in combination to achievethe result of a functional module.

The disclosure of this patent document incorporates material which issubject to copyright protection. The copyright owner has no objection tothe facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the Patent and Trademark Officepatent file or records, for the limited purposes required by law, butotherwise reserves all copyright rights whatsoever.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example, and notlimitation. It will be apparent to persons skilled in the relevantart(s) that various changes in form and detail can be made thereinwithout departing from the spirit and scope. In fact, after reading theabove description, it will be apparent to one skilled in the relevantart(s) how to implement alternative embodiments. Thus, the presentembodiments should not be limited by any of the above describedexemplary embodiments. In particular, it should be noted that, forexample purposes, the above explanation has focused on the example(s)using LAA communication systems. However, one skilled in the art willrecognize that embodiments of the disclosure may also be implemented ina system comprising one or more TDD cells (e.g. frame structure 2 and/orframe structure 1). The disclosed methods and systems may be implementedin wireless or wireline systems. The features of various embodimentspresented in this disclosure may be combined. One or many features(method or system) of one embodiment may be implemented in otherembodiments. Only a limited number of example combinations are shown toindicate to one skilled in the art the possibility of features that maybe combined in various embodiments to create enhanced transmission andreception systems and methods.

In addition, it should be understood that any figures which highlightthe functionality and advantages, are presented for example purposesonly. The disclosed architecture is sufficiently flexible andconfigurable, such that it may be utilized in ways other than thatshown. For example, the actions listed in any flowchart may bere-ordered or only optionally used in some embodiments.

Further, the purpose of the Abstract of the Disclosure is to enable theU.S. Patent and Trademark Office and the public generally, andespecially the scientists, engineers and practitioners in the art whoare not familiar with patent or legal terms or phraseology, to determinequickly from a cursory inspection the nature and essence of thetechnical disclosure of the application. The Abstract of the Disclosureis not intended to be limiting as to the scope in any way.

Finally, it is the applicant's intent that only claims that include theexpress language “means for” or “step for” be interpreted under 35U.S.C. 112. Claims that do not expressly include the phrase “means for”or “step for” are not to be interpreted under 35 U.S.C. 112.

1. A method comprising: receiving by a wireless device: a first maximumtotal transmit power allowed for a first cell group of a first type ofradio access technology; and a second maximum total transmit powerallowed for a second cell group of a second type of radio accesstechnology that is different from the first type of radio accesstechnology; determining a total transmission power exceeds a powervalue, wherein the total transmission power is based on: a first powerfor transmission of one or more first uplink signals via the first cellgroup, wherein the first power is less than or equal to the firstmaximum total transmit power; and a second power for transmission of oneor more second uplink signals via the second cell group, wherein thesecond power is less than or equal to the second maximum total transmitpower; and dropping scheduled transmission of the one or more firstuplink signals of the first cell group in response to the first cellgroup being of the first type of radio access technology; andtransmitting, to a base station, at least one of the one or more seconduplink signals.
 2. The method of claim 1, further comprising receiving,from the base station, one or more radio resource control (RRC) messagescomprising first configuration parameters of a plurality of cellsgrouped in a plurality of cell groups comprising: the first cell groupcomprising one or more first cells of the first type of radio accesstechnology; and the second cell group comprising one or more secondcells of the second type of radio access technology.
 3. The method ofclaim 1, wherein the power value is a maximum transmit power of thewireless device.
 4. The method of claim 1, wherein the totaltransmission power exceeds the first power value comprises when a sum ofthe first power and second power exceeds a maximum transmit power of thewireless device.
 5. The method of claim 1, wherein: the first type ofradio access technology operates in a licensed band; and the second typeof radio access technology operates in an unlicensed band.
 6. The methodof claim 1, wherein the second type of radio access technology operatesaccording to a release of LTE technology.
 7. The method of claim 1,wherein the one or more first uplink signals comprise one or more firstsounding reference signals.
 8. The method of claim 1, wherein the one ormore first uplink signals comprise one or more first physical uplinkshared channel signals.
 9. The method of claim 1, wherein the powervalue depends on whether at least one cell in the first cell group isactivated.
 10. The method of claim 1, wherein the dropping the scheduledtransmission of the one or more first uplink signals of the first cellgroup is based on at least one uplink channel transmit power priority.11. A wireless device comprising: one or more processors; and memorystoring instructions that, when executed by the one or more processors,cause the wireless device to: receive: a first maximum total transmitpower allowed for a first cell group of a first type of radio accesstechnology; and a second maximum total transmit power allowed for asecond cell group of a second type of radio access technology that isdifferent from the first type of radio access technology; determine atotal transmission power exceeds a power value, wherein the totaltransmission power is based on: a first power for transmission of one ormore first uplink signals via the first cell group, wherein the firstpower is less than or equal to the first maximum total transmit power;and a second power for transmission of one or more second uplink signalsvia the second cell group, wherein the second power is less than orequal to the second maximum total transmit power; and drop scheduledtransmission of the one or more first uplink signals of the first cellgroup in response to the first cell group being of the first type ofradio access technology; and transmit, to a base station, at least oneof the one or more second uplink signals.
 12. The wireless device ofclaim 1, wherein the instructions, when executed by the one or moreprocessors, further cause the wireless device to receive, from the basestation, one or more radio resource control (RRC) messages comprisingfirst configuration parameters of a plurality of cells grouped in aplurality of cell groups comprising: the first cell group comprising oneor more first cells of the first type of radio access technology; andthe second cell group comprising one or more second cells of the secondtype of radio access technology.
 13. The wireless device of claim 1,wherein the power value is a maximum transmit power of the wirelessdevice.
 14. The wireless device of claim 1, wherein: the first type ofradio access technology operates in a licensed band; and the second typeof radio access technology operates in an unlicensed band.
 15. Thewireless device of claim 1, wherein the second type of radio accesstechnology operates according to a release of LTE technology.
 16. Thewireless device of claim 1, wherein the one or more first uplink signalscomprise one or more first sounding reference signals.
 17. The wirelessdevice of claim 1, wherein the one or more first uplink signals compriseone or more first physical uplink shared channel signals.
 18. Thewireless device of claim 1, wherein the power value depends on whetherat least one cell in the first cell group is activated.
 19. The wirelessdevice of claim 1, wherein the dropping the scheduled transmission ofthe one or more first uplink signals of the first cell group is based onat least one uplink channel transmit power priority.
 20. A method foruse in a wireless device, the method comprising: receiving: a firstmaximum total transmit power allowed for a first cell group of a firsttype of radio access technology; and a second maximum total transmitpower allowed for a second cell group of a second type of radio accesstechnology that is different from the first type of radio accesstechnology; determining a total transmission power exceeds a powervalue, wherein the total transmission power is based on: a first powerfor transmission of one or more first uplink signals via the first cellgroup, wherein the first power is less than or equal to the firstmaximum total transmit power; and a second power for transmission of oneor more second uplink signals via the second cell group, wherein thesecond power is less than or equal to the second maximum total transmitpower; and dropping scheduled transmission of the one or more firstuplink signals of the first cell group in response to the first cellgroup being of the first type of radio access technology; andtransmitting, to a base station, at least one of the one or more seconduplink signals.